Optical and electrical changes in several kinds of organic films after ion implantation were investigated. Vacuum evaporated organic films were irradiated by 30-100 keV N+ ion beam. The ion dose was varied from 10(14) to 10(16) ions/cm(2). The surface resistivity varies 9 orders of magnitude from the order of 10(17) ohm/(square) to 10(8) ohm/(square). Furthermore, the film color changes to dark brown with increasing dose, and main optical absorption peaks of the organic molecule itself decreased. The electrical and optical changes by ion implantation seem to reflect chemical elements and physical properties of these films originated from the molecular structure. Furthermore, the large increase in conductivity by ion beam irradiation is due to the formation of carbon clusters in the organic films. These experimental results suggest that the modification of optoelectric properties and three dimensional wiring in organic films by ion implantation are promising techniques for molecular electronic devices.